Insulin is a hormone that lowers the level of glucose (a type of sugar) in
the blood. It's made by the beta
cells of the pancreas and released into the blood when the glucose level goes up,
such as after eating. Insulin helps glucose enter the body's cells, where it can be
used for energy or stored for future use. In diabetes, the pancreas doesn't make enough
insulin or the body can't respond normally to the insulin that is made. This causes
the glucose level in the blood to rise.